Seres Therapeutics Presents Preclinical Data at Digestive Disease Week (DDW) 2026 Supporting SER-603, a Next-Generation Cultivated Live Biotherapeutic Candidate, for Inflammatory Bowel Disease
Data highlight both SER-603's rational design that targets microbial functions linked to mucosal healing and gastrointestinal inflammation in IBD, as well as the advancement of microbiome-based biomarkers that inform response to biologics and patient stratification
Presentation selected for DDW ‘Poster of Distinction' recognition
CAMBRIDGE, Mass., May 04, 2026 (GLOBE NEWSWIRE) -- Seres Therapeutics, Inc. (NASDAQ:MCRB) (Seres or the Company), a leading live biotherapeutics company, today announced new preclinical data supporting the design and potential of SER-603, a next-generation cultivated live biotherapeutic candidate for inflammatory bowel disease (IBD), being presented at Digestive Disease Week (DDW) 2026, taking place May 2–5, 2026, in Chicago, IL. The poster, titled "The Rational Design of SER-603: A Next Generation Cultivated Microbial Consortia to Treat IBD," which has been selected as a DDW ‘Poster of Distinction,' highlights Seres' integrated approach to the design of microbiome therapeutics, combining rational strain selection and a novel biomarker-driven patient stratification.
"We are advancing next-generation live biotherapeutics through a rational, data-driven design strategy to address underlying drivers of IBD that current therapeutics do not," said Matthew Henn, Ph.D., President and Chief Scientific Officer of Seres. "SER-603 is designed to enable more precise modulation of inflammatory pathways relevant to IBD by combining the targeting of microbial functions linked to epithelial barrier integrity and mucosal healing with a biomarker-based approach to patient stratification. By leveraging insights from clinical datasets and translational models, we have developed a consortium intended to achieve durable drug strain engraftment and targeted modulation of disease-relevant inflammatory pathways. We are advancing SER-603 through IND-enabling activities and have engaged potential collaborators to support clinical development, including evaluation as both a monotherapy and in combination with existing treatment approaches."
Current therapies for IBD focus primarily on the downstream consequences of inflammation, specifically suppressing cytokine-induced inflammation by broadly suppressing the immune system, and do not address two additional drivers of disease: mucosal barrier compromise and inflammation inducing bacteria in the gastrointestinal (GI) tract. SER-603 is optimized to modulate the GI microbiome to reduce microbial inflammatory stimuli, induce mucosal healing and reduce barrier damage that can allow translocation of inflammatory bacteria and molecules. The mechanisms of action of SER-603 are complementary to existing therapeutics, providing the opportunity for both mono- and combination therapy, potentially without added toxicities given live biotherapeutics historical favorable safety profile. SER-603 incorporates strains selected for engraftment and delivery of clinically relevant metabolites, including short-chain fatty acids, secondary bile acids, and tryptophan-derived molecules, with a therapeutic goal of inducing mucosal healing and regulating inflammatory pathways central to IBD pathophysiology, without immunosuppression. Its design integrates insights from human clinical datasets and reverse translational approaches to identify strains linked to key functional outputs, enabling targeted modulation of inflammatory microbiome features, and is complemented by microbiome-based biomarkers associated with GI inflammation, to support patient stratification and to enrich for those most likely to benefit. In the MiGUT in vitro gut model, which recapitulates patient-derived IBD microbiomes, SER-603 reduced inflammatory cytokine production across multiple samples, supporting its potential to impact disease-relevant biology and providing translational support for its mechanism of action.
Presentations Details
Poster Presentation (Su1462)
Title: The Rational Design of SER-603: A Next Generation Cultivated Microbial Consortia to Treat IBD
Session: 7165
Date and Time: May 3 at 12:30-1:30 pm
Presenter: Nicholas Beauchemin
About Seres Therapeutics
Seres Therapeutics, Inc. (NASDAQ:MCRB) is a clinical-stage biotechnology company developing novel live biotherapeutics, with a focus on inflammatory and immune diseases. The Company led the development and FDA approval of VOWST™, the first orally administered microbiome therapeutic, which was subsequently divested to Nestlé Health Science. SER-155, which has received Breakthrough Therapy and Fast Track designations, is being advanced for patients undergoing allogeneic hematopoietic stem cell transplant (allo-HSCT), and is Phase 2 ready, pending receipt of funding. An investigator-sponsored trial of SER-155 is ongoing in immune checkpoint inhibitor–related enterocolitis (irEC) to further evaluate the potential breadth of the Company's live biotherapeutic platform. SER-603, in development for irritable Inflammatory bowel disease, is designed to modulate the gastrointestinal microbiome and support mucosal barrier integrity by targeting inflammatory bacteria and associated metabolites. For more information, please visit www.serestherapeutics.com.
Forward-Looking Statements
This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. All statements contained in this press release that do not relate to matters of historical fact should be considered forward-looking statements, including statements about: the anticipated content and timing of upcoming presentations and conferences; the design, timing and results of our pre-clinical and clinical studies and data readouts; current or future product candidates and their potential impacts and outcomes; clinical development plans and commercial opportunities; our efforts to create a strategic, R&D, or other partnership; the advancement of IND-enabling activities; our ability to operationalize a study upon receipt of any financing; our planned strategic focus; the anticipated timing of any of the foregoing; and other statements that are not historical fact.
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